1. Field of the Invention
This invention relates to the use of phenylphosphonic acids and salts thereof to stabilize aqueous hydrogen peroxide solutions.
2. Description of the Prior Art
Dilute aqueous hydrogen peroxide in concentrations of from about 3 to about 10 weight percent has many uses, including bleaching, hair dyeing and waving, processing of photographs for permanence, and preparation of cosmetics and mild antiseptics.
Hydrogen peroxide is sold in concentrated aqueous solutions of between about 30 and 90 weight percent, which are ofted diluted by the purchaser for use or sale. The concentrated solutions are quite stable when pure, but contaminants which promote decomposition may be introduced in storage and handling. The common use of tap water for dilution of the concentrate may introduce significant quantities of decomposition-inducing cations such as iron, copper, and manganese cations. If the diluted solutions are stored rather than used immediately, substantial decomposition may occur.
Numerous organic and inorganic stabilizers for aqueous hydrogen peroxide are known. Various combinations of stannate, nitrate, orthophosphate, and pyrophosphate ions for use at varying pH have been proposed. See, for example, U.S. Pat. Nos. 3,701,825, 3,373,113, 3,591,341, and 3,607,053. U.S. Pat. No. 3,687,627 shows the use of alkylidene diphosphonic acids in aqueous hydrogen peroxide in combination with stannate and magnesium ions.
U.S. Pat. No. 2,230,371 discloses phosphonic acids, including phenylphosphonic acid, are useful in stabilizing organic substances such as gasoline, fats, oils, and cotton against copper-promoted oxidation.
U.S. Pat. No. 3,781,409 describes aqueous hydrogen peroxide solutions stabilized with water-soluble tin compounds, preferably in combination with a complexing agent such as a phosphonic acid. Specific phosphonic acids mentioned are hydroxyethylidene diphosphonic acids, nitrilo tri(methylenephosphonic acid), ethylenediamine tetra(methylphosphonic acid), and alkali metal, ammonium, substituted ammonium, magnesium, and other salts thereof.
Other U.S. patents which disclose the use of alkylidene diphosphonic acid, amino tri(alkylidenephosphonic acid), and ethylenediamine tetra(alkylidenephosphonic acid) compounds to stabilize aqueous hydrogen peroxide are U.S. Pat. Nos. 3,122,417, 3,701,825, 3,681,022, and 3,903,244.